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Ultra-high Resolution Space-VLBI Imaging of Jets in Nearby AGN Tuomas Savolainen Aalto University Metsähovi Radio Observatory, Finland Max-Planck-Institut für Radioastronomie, Germany On behalf of the RadioAstron Nearby AGN Key Science Program team: J.Anderson, U.Bach, B.Boccardi, C.Casadio, G.Bruni, P.Edwards, J.Eilek, C.Fromm, G.Giovannini, M.Giroletti, K.Hada, P.Hardee, Y.Hagiwara, J.Hodgson, M.Honma, M.Kino, Y.Y.Kovalev, T.Krichbaum, A.Lobanov, S.S.Lee, D.Meier, M.Orienti, H.Nagai, S.O’Sullivan, C.Reynolds, B.W.Sohn, K.V.Sokolovsky, S.Tingay, J.A.Zensus
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RadioAstron Space-VLBI Project 10-m orbiting antenna Launched in July 2011 Highly elliptical orbit: baselines from ~1000 km to 350000 km Works together with the largest ground radio telescopes to form an ultra high resolution interferometer Receivers onboard: 0.33, 1.6, 5 and 18-25 GHz Max. angular resolution: 7µas 32 MHz bandwidth, dual-pol. Project led by the Astro Space Center of Lebedev Physical Institute, Russia Kardashev+ 2013
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RadioAstron Nearby AGN Key Science Program
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FIRST RESULTS: SPACE-VLBI IMAGES OF 3C84
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3C84 on Sep 21 2013 5 GHz 22 GHz 5/22 GHz
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3C84 RadioAstron observations on Sep 21 2013 (5/22 GHz) 5 GHz fringe on RA-EF baseline 6.9ED (1.4Gλ) SNR = 8.6
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3C84 5 GHz RadioAstron image Ground-VLBI image 5 GHz 43 GHz VLBA Jan 2013 Nagai et al. (2014) Space-VLBI image 5GHz 1 mas 0.35 pc T b > 1x10 12 K ? (u,v) range 0-700Mλ Beam: 0.9x0.5mas C3 is a slow feature related to the restarted jet activity in the 2000s (Suzuki+ 2012)
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3C84 22 GHz RadioAstron image 1 mas 0.35 pc Beam: 0.03x0.32 mas Full resolution
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3C84 22 GHz RadioAstron image 1 mas 0.35 pc “Hot spot” Mach disk / reverse shock? Core Beam: 0.05x0.15 mas Slightly super- resolved in one direction Clearly edge-brightened jet Hot spot inside the moving feature C3 – the structure resembles that commonly seen in simulations of a working surface between jet and ambient medium
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3C84 core structure 0.3 mas 0.1 pc 0.06x0.06mas “super-resolved” Strongly super- resolved in one direction Core is resolved in direction transverse to the jet – the brightest feature is in the middle of the flow Edge-brightened emission upstream of the core What is the core here? A re-collimation shock? The base of jet? GMVA Hodgson et al. Preliminary
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More early results: M87 space fringes detected 5 GHz 22 GHz Mostly no detections on baselines longer than Earth diameter no ultra-compact structure brighter than RA detection limit Baseline stacking could yield a few more detections, though Imaging in progress
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Summary
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BACKUP SLIDES
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Nearby AGN KSP observations in AO-1 3C 84 5/22 GHz Sep 21 ’13 M87 5/22 GHz Feb 4 ’14 M87 1.6 GHz Jun 4 ’14 Cen A 5/22 GHz Feb 13 ’14 Cen A 22 GHz Mar 27 ’14 ~10 D Earth 30 ground stations 33 ground stations 30 ground stations 5 ground stations ~11 D Earth ~6 D Earth ~4 D Earth 6 ground stations
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Residual acceleration of the RadioAstron
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3C84 at 5GHz RadioAstron visibilities Green: Ground-ground baselines Black: Baselines to RadioAstron
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3C84 at 5GHz - calibration accuracy of the SRT Green: Ground-ground baselines Black: RadioAstron-Kalyazin baseline (<1ED)
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3C84 at 5GHz with space baselines RA data and ground-only model RA data and ground+space model
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3C84 at 5GHz ground-only image
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3C 84 at 5GHz – Full resolution uvw 2,-0.5uvw 2,0
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3C84 - Other frequencies 5 GHz 1 mas 15 GHz Peak: 1.5 Jy/beam beam 0.9x0.5mas 43 GHz 5 GHz Core Peak: 5.3 Jy/beam beam 0.8x0.3mas Peak: 2.5 Jy/beam beam 0.4x0.15mas
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3C84 - Spectra 15-43 GHz spectral index +1.1 -0.5 5-15 GHz spectral index +1.8 +1.3 +1.1 C1, C2 and C3 ALL have inverted spectrum at 5GHz C3 C2 C1
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